US2265254A - Range and phase finder for synchronous telegraph systems - Google Patents

Description

1941- J. A. SPENCER 2,265,254

RANGE AND PHASE FINDER FOR SYNCHRONOUS TELEGRAPH SYSTEMS Filed April 29, 1939 INVENTOR. JAMES A. SPENCER ATTORNEY.

Patented Dec. 9, 1941 UNITED STATES PATENT OFFICE RANGE AND PHASE FINDER FOR SYNCHRO NOUS TELEGRAPH SYSTEMS James A. Spencer, Teaneck, N. J., assignor to Radio Corporation of America, a corporation of Delaware Application April 29, 1939, Serial No. 270,717

3 Claims.

marking impulses comprehended in an equal length code signal may be selectively applied to the decoding apparatus for actuating a printer.

Inorder that the receiving apparatus, especially the receiving distributor, may be correctly synchronized and phased with respect to the incoming signals it has been necessary heretofore to observe the operation of the printer while controlling the distributor orientation. In such cases it is found advantageous to employ predetermined test signals and to adjust the orientation of the distributor segments with respect to the distributor brush by reference to the effects produced upon the printer. It is frequently desirable, however, to locate the printer at some point remote from the distributor so that it is quite inconvenient, if not impossible, to follow the printer operation while attempting to orient i the distributor. Furthermore, it has been found necessary to employ two distinct types of test signals,. one for phasing and the other for range finding. By phasing is meant the assignment of each of the multiplex signals to appropriate printer units. By range finding is meant the more refined orientation of the distributor segments so that the marking impulses shall fall as nearly as possible upon the center portions of each distributor segment.

It is an object of my invention to provide phase and range finding apparatus for use in synchronous multiplex telegraph operation such that an indication may be had in close proximity to the receiving distributor. The indications so provided may then be utilized for purposes of orienting the distributor with respect to the incoming signals.

It is another object of my invention to provide a phase and range indicating device in combination with a synchronous telegraph receiving distributor and in combination with other telegraph apparatus such that synchronous correction of the receiving distributor may be monitored.

Other objects and advantages of my invention will be made clear by the following description when read in view of theaccompanying drawing, the sole figure of which represents diagrammaticallythe essential elements of a preierred embodiment and more particularly the circuit arrangement which is relied upon for performing the functions of the apparatus.

Referring to the drawing, I show therein in blockdiagram a conventional locking circuit [0 which has input leads and an output circuit feeding to the polarized relay 2|. The incoming signals may be derived from a line or a radio channel. The details of the locking circuit are not shown as they are well understood in this art. They usually comprise an arrangement of. electron discharge tubes having a trigger action such that very short "impulses representing the components of a code signal are shaped into more prolonged controlling impulses of square wave formation suitable for actuating a relay such as that shown at 2|. This relay may be polarized as indicated conventionally or it may be a biased relay of any suitable type. The armature 22 of this relay is controlled for impressing marking and spacing impulses upon a distributor ring 9, these impulses being derived from any suitable direct current source 23. The distributor as shown includes in addition to the ring 9 a plurality of segments one series of which is numbered from 1 to 7 inclusive. These segments are identified with the respective units of a uniform length code signal. Other segments in the outer ring of the distributor may be employed, if desired, to distribute the elements of other code signals to their appropriate printer units as, for example, when the system is used in multiplex telegraphy. The distributor as shown has 21 conductive segments in the outer ring and hence is suitable for synchronous transmission of code signals such as for simultaneously actuating three separate printers.

According to conventional practice the solid ring 9 and the segments of the outer ring are all mounted on a common face plate 24. Hence the segments may be oriented either clockwise or counter-clockwise to adjust the effective phase of the brush 8, without varying the speed of the latter.

The conductive segments of the distributors are separated by insulation segments which subtend sufficient arcs so that when the distributor is properly phased the brush 8 will be passing over an insulation segment while the armature 22 is allowed time to travel from one to the other of its companion contacts. Although the armature travel time is very small it is important that it shall take place as nearly as possible at the mid-point of passage of the brush 8 over an insulation segment.

Since thebircuit arrangement for one printer is the same as that of the others only the circuits appropriate to one printer and its associated apparatus have been shown in the drawing.

The brush 8 mounted on a brush arm is synchronously driven by a suitable motor, not shown. The outer ring of distributor segments may be rotated with respect to the stator of the motor for the purpose of properly orienting the distributor with respect to the incoming signals.

correcting device, in which case the brusharm would be advanced or retarded according to requirements.

Each of the segments l to inclusive co;

nected respectively with an appropriate magnet II to I! inclusive constituting a portion of the conventional decoding means which maybe employed in a receiving telegraph printer. The

"details of the printer are not otherwise shown as they are well known in the art. It is also understood how the magnets H to I! inclusive may be caused to actuate different code bars, or devices for character type selection, thereby to control the operation of the printer in response to the received signals.

segment.

Each of the segments 2, 4 and 6 is connected by a branch circuit to one of the glow discharge tubes 32, 34 and 36 respectively. These branch circuits are completed through the glow discharge tubes to a common return circuit which may be grounded, if desired.

In the operation of my invention for testing the distributor orientation and for adjusting the same, it is desirable that a test signal be transmitted such that three marking elements shall be uniformly spaced apart by intervening spacing units of the same code signal. When such 'a test signal is applied to only one particular channel, which is selected for test purposes, the resulting indications are sufiicient for properly orienting the distributor. If the test signal falls haphazardly upon the distributor segments, it is unlikely that any of the glow tubes 32, 3d and 36 will be ignited. The distributor ring is, therefore, rotated with respect to the field of the motor until all three of the glow tubes light up in response to the uniformly spaced marking ele- -ments of the test signal. the marking impulses it is definitely known that By this response to the correct phase has been found. In other words, it can be seen that the signal itself is confined to that part of the distributor between the index points it and 19. Printer code signals subsequently transmitted on each of the channels will then be fully spread over the distributor segments appropriate thereto, and successive control of the respective printer units will be conformed to the channel separation of the code signals. If the test signal were to be applied so as to overlap the arc of the distributor ring between the index points l8 and I9, either no lamps would be 10. As an alternative the motor stator may be made rotatable in response to the'operation' of a phase" lighted or possibly only one or two of the same would be observed to glow. Correspondingly, if the signal were to be delayed so that it overlapped the two arcs comprehended from the index points from l8 through H! to 25], then one or both of the lamps 34 and 36 might be ignited or else none at all. It is clear, therefore, that perfect phasing of the distributor is indicated only when all three of the lamps 32, 34 and 36 are ignited.

It will be understood that the glow discharge tubes may be'of the gaseous type, which comprehends, for example, neon lamps. In practice the brush passes over the different segments of the distributor so rapidly that it rotates through one revolution in .less time than the persistence of vision, or atleast it is only possible for an observer to note that the lamps when ignited produce a flickering eiiect. This is true even though it is a characteristic of the neon lamp to be completely extinguished at the instant when it ceases to pass current.

When the invention is to be used for range finding, the distributor ring may be oriented either clockwise or counter-clockwise until, theoretically, all three lamps are extinguished by such orientation. In practice, due to the effects of signal distortion, only one of the lamps is completely extinguished while the other two exhibit a dim flicker. The ring may then be rotated in the opposite direction through the are which enables the lamps to be fully ignited and until they become practically extinguished again. The length of the arc of distributor segment rotation which represents continuous ignition of the neon lamps represents the range. Accordingly the position of the distributor segments mid-way between the points where the lamps are extinguished is the proper position for reliable decoding of the signals.

It will be apparent from the above description that the combination of the glow discharge tubes with the operating circuits in the manner shown permits the phase and range finding operation to be performed by one who is tending the distributor itself, irrespective of the location of the printer. In fact, by placing the indicator lamps 32, 3 1 and 36 in proximity to the distributor it is possible to locate the printer at any convenient point whether near to or remote from the distributor.

Other applications of my invention besides those specifically shown and described may be understood as comprehended within the scope of the invention. The invention itself is, therefore, limited only as defined by the claims.

I claim:

1. In combination with a receiving distributor having a plurality of conductive segments each appropriate to one of the respective units of an .equal length code signal, printing telegraph apparatus having signal de-coding means connected in parallel circuits each of which includes a respective one of said segments, a'plurality of glow discharge tubes, circuits individually connected between respective ones of said tubes and such of said segments as are spaced apart by intervening conductive segments, a source of operating potential, and signal-responsive relay means for selectively applying current to said circuits thereby to actuate both the signal de-coding means and the glow discharge tubes.

2. The combination according to claim 1 and including a unitary mounting means for said dis,- tributor segments, said mounting means being marking units for causing one or more of said tubes to glow, and means including a brush rotatable over said segments and operative when said segment supporting means has been oriented to the point where the test signal causes all of said tubes to glow, for passing each marking impulse of a character code signal of uniform length through appropriate segments of said series to the respective de-coding magnets for 10 which said impulses are intended.

JAMES A. SPENCER.

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